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Chapter 2 Function Reference — DIG_DB_Transfer
NI-DAQ FRM for PC Compatibles 2-162
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National Instruments Corporation
DIG_DB_Transfer
Format
status = DIG_DB_Transfer (deviceNumber, group, halfBuffer, ptsTfr)
Purpose
For an input operation, DIG_DB_Transfer waits until NI-DAQ can transfer half the
data from the buffer being used for double-buffered digital block input to another buffer,
which NI-DAQ passes to the function. For an output operation,
DIG_DB_Transfer waits
until NI-DAQ can transfer the data from the buffer passed to the function to the buffer being
used for double-buffered digital block output. You can execute
DIG_DB_Transfer
repeatedly to read or write sequential half buffers of data.
Parameters
Input
Input/Output
Parameter Discussion
group is the group to be configured.
Range: 1 or 2.
halfBuffer is the integer array to which or from which NI-DAQ is to transfer the data. The
size of the array must be at least half the size of the circular buffer being used for the
double-buffered digital block operation.
ptsTfr is only used for output groups with partial transfers enabled. If you have set the partial
transfer flag, NI-DAQ can make a transfer to the digital output buffer of less than or equal
to half the buffer size, as specified by this field. However, the function will halt the
double-buffered digital operation when NI-DAQ makes a transfer of less than half the buffer
Name Type Description
deviceNumber i16 assigned by configuration utility
group i16 group
ptsTfr u32 points to transfer
Name Type Description
halfBuffer [i16] array to which or from which the data is to be
transferred